Clamps for use in aligning the confronting ends of a pair of pipe sections are well known. Among the best known clamps are those of the kind embodying the inventions disclosed in Dearman Pat. Nos. 3,653,574; 3,901,497; 3,944,202; and 4,586,647. Each of these patents discloses a clamp having a chain of such length as to encircle one of the pipes adjacent its end. The chain is secured at one end to a main block or head member via a fine adjusting mechanism, whereas the opposite end of the chain is threaded through an opening provided in the head and retained therein by a latching mechanism so as to enable the chain to form a loop. That end of the chain which is fixed to the fine adjusting mechanism then may be adjusted so as to expand or contract the loop, as desired. The chain is provided at spaced intervals circumferentially of the loop with a plurality of supports which extend beyond the end of the pipe on which the chain is mounted so as to provide support for the confronting end of the other pipe.
A particular advantage of the known clamps referred to above of is that the size of the loop in each case is adjustable within wide limits, thereby making it possible for a single clamp to be used with pipes of greatly different diameters. In these clamps, however, the presence of a main block or head, separate retaining means, and separate fine adjusting means results in a fairly large number of separate parts, which is reflected in the cost of manufacturing the clamps, as well as in the weight of such clamps. Both cost and weight are important considerations for obvious reasons.
Other aligning clamps are known. Typical of such other clamps are those shown in Watson Pat. Nos. 3,467,295 and 3,666,159; Mori Pat. No. 3,593,402; and Olson Pat. No. 3,705,453. The clamps typified by those disclosed in these patents provide for little, if any, adaptability of such clamps to pipes of greatly different diameters Further, they do not provide for accurate location of the second pipe supports where desired, nor do they make it possible for the clamping chain or other force applying means to be substituted at will for similar chains and the like of different lengths.
Apparatus constructed in accordance with the invention retains the advantageous characteristics of the known clamps, but overcomes or greatly minimizes their disadvantages.